At the above mentioned glazing systems, the glass elements may be in the form of single glass or in the form of sealed glazing units with two or more glass sheets that are stuck to each other with air or gas-filled spaces. At a typical such arrangement with sealed glazing units, the glass elements are constituted by an inner and an outer glass sheet, where the latter shall form the façade surface of the glazing. The two glass sheets are joined together with an intermediate frame, which, at least at the side edges of the glass elements, is indented from these edges, at which a groove from the respective edge thereby is formed. When the glass elements are mounted with the edges of their outer glass sheets adjacent to each other, there shall be slots on the inside between the inner glass elements.
In an assembled condition, the glass elements are supported by the supporting frame of the building, which is situated inside the façade. At the lower edge of the respective glass element, the supporting elements extend from the frame and in under it. At said design with sealed glazing units, the supporting elements extend into said slot, such that the inner glass sheet can rest against the supporting element with its lower edge. In this way, the weight of the glass element supported by the frame via the supporting elements. Besides, it is required that the glass elements are retained that they do not tip and fall outwards or inwards. For retaining the glass elements, attachment elements which are connected with the building frame are provided, which attachment elements extend in over the side edges of the glass elements and grip around these. For the design with double glass sheets, the attachment elements extend in said slot at the side edges of the glass elements and into said groove at these edges, in a position where they grip around the edge of the inner glass sheet. This retaining must resist relatively large forces, especially wind forces, which strive to press the glass elements inwards or pull them outwards.
In order to enable the supporting elements to extend under the respective glass element and to enable the attachment elements to grip around the side edges of the glass elements, it is required that slots are left between the edges of these when the glass elements are made as single glass. For the design with double glasses in the glass elements, slots are required at the edges only for the innermost glass sheets, while the outer may be joined edge to edge.
A typical such a retaining arrangement is disclosed in U.S. Pat. No. 5,199,236 (Allen). In a cross section in the patent document (FIG. 3) through two adjacent side edges of two glass elements, the above mentioned embodiment with grooves that extend inwards from the side edges of the glass sheets to the joining frame element is apparent. In a slot between the edges of the two inner glass sheets, the retaining elements extend, which are joined with the building frame, which is shown in the form of a shaped hole beam. It is desired that the slot between the outer glass elements is as small as possible, partly to render the joint as little visible as possible and partly to decrease the consumption of sealing compound in the joint during sealing of a mounted façade and also to reduce the amount of work for application of said sealing compound after the glass elements have been mounted. For sealed glazing units this may be achieved by means of a design where the edges of the outer glass sheet are protruding in relation to the inner, where there has to be a slot for the insertion of the supporting and retaining elements. This presumes, however, that a broad outer slot does not have to be arranged in order to provide access to, for example, the attachment elements from the outside during mounting.
At the attachment elements, which shall grip around the edge of the glass sheet, there is a risk that the edge is broken if the mounting is too rigid. Should such breakage occur, and the risk is especially large when large wind forces appear, this may result in that the glass element tips outwards and, falls down, which, of course, is a catastrophe. The risk for the occurrence of this increases with the size of the glass element. Large elements are often desired, due to the fact that these have a lesser length for outer joints and due to the fact that the supporting frame on the inside may be made to be more free. The latter is especially interesting with so called outrigged systems, where the frame does not constitute an actual building part, but only has the function to support a glass wall. In order to provide for this wall to stand as freely as possible, the frame is thus made with beams and sometimes also with firmly tightened steel wires at a distance from the inner glass surface and joining the frame and the supporting and attachment elements of the glass elements with supports.